regex behavior question

[mwpclark]

Hi

I have 2 regex codes:

This works:

perl -e "s/\&\#39\;/\'/g" -p -i file.txt

This does not work:

perl -e "s/\&\#39\;/\'/g" -pi file.txt

The only difference is the -pi versus -p -i.

The -pi version seems to work for other substitutions, just not this one. The only difference there is this is enclosed in double quotes (so that I can use the \').

Can somebody explain why one works and the other does not?

Thanks
Mike

 

[KevinADC]

generally that is written like this:

perl -pi -e "s/\&\#39\;/\'/g" file.txt

or:

perl -p -i -e "s/\&\#39\;/\'/g" file.txt

The code wrapping quotes are important, double-quotes works on Windows, but not Unix/Linux, single-quotes are used for those. Not sure what a Mac uses. Also on Windows you may need to define what -i is, like '.bac' or whatever.

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- Kevin, perl coder unexceptional!

 

[mwpclark]

Thanks Kevin

I have found that double quotes work on linux as well as single, and that when replacing a single quote within the string I have to enclose in double quotes.

But I don't understand why -p -i works with this string but not -pi

 

[KevinADC]

Might have something to do with the syntax or the operating system but I just don't know.

------------------------------------------
- Kevin, perl coder unexceptional!

 

[Annihilannic]

When you say it doesn't work... how exactly doesn't it work? Do you get an error message? Does the replacement not occur? Is a backup of the original file created with an unexpected name?

Annihilannic.

 

[Annihilannic]

Both forms seem to work as expected for me (tested under ksh 88, HP-UX 11.11, perl 5.8.0).

Annihilannic.